A low-emissivity glass refers to a glass in which a low-emissivity layer containing a metal having high reflectivity in an infrared region such as silver (Ag) is deposited as a thin film. The low-emissivity glass is a functional material having an energy saving effect of buildings by reflecting radiant rays in the infrared region to block outdoor solar radiant heat in summer and to preserve interior heat radiant heat.
Silver (Ag) generally used as the low-emissivity layer is oxidized when being exposed during air, such that dielectric layers are deposited as anti-oxidation films on an upper part and a lower part of the low-emissivity layer. The dielectric layers serve to increase visible light transmittance.